npRmpi (version 0.60-20)

mpi.gather.Robj: Extentions of MPI_Gather and MPI_Allgather APIs

Description

mpi.gather.Robj gathers each member's object to the member specified by the argument root. The root member receives the objects as a list. mpi.allgather.Robj is the same as mpi.gather.Robj except that all members receive the result instead of just the root.

Usage

mpi.gather.Robj(obj=NULL, root = 0, comm = 1, ...)
mpi.allgather.Robj(obj=NULL, comm = 1)

Value

For mpi.gather.Robj, it returns a list, the gathered message for the root member. For

mpi.allgatherv.Robj, it returns a list, the gathered message for all members.

Arguments

obj

data to be gathered. Could be different type.

root

rank of the gather

comm

a communicator number

...

optional arugments to sapply.

Author

Hao Yu and Wei Xia

Details

Since sapply is used to gather all results, its default option "simplify=TRUE" is to simplify outputs. In some situations, this option is not desirable. Using "simplify=FALSE" as in the place of ... will tell sapply not to simplify and a list of outputs will be returned.

References

https://www.mpich.org/, https://www.mpich.org/static/docs/latest/www3/

See Also

mpi.gather, mpi.allgatherv.

Examples

if (FALSE) {
# Not run in checks: requires pre-spawned slaves and a live worker communicator.
#Assume that there are some slaves running
mpi.bcast.cmd(id<-mpi.comm.rank())
mpi.bcast.cmd(x<-rnorm(id))
mpi.bcast.cmd(mpi.gather.Robj(x))
x<-"test mpi.gather.Robj"
mpi.gather.Robj(x)

mpi.bcast.cmd(obj<-rnorm(id+10))
mpi.bcast.cmd(nn<-mpi.allgather.Robj(obj))
obj<-rnorm(5)
mpi.allgather.Robj(obj)
mpi.remote.exec(nn)
}